Micrometer dial mechanism



Patented Feb. 9, 1954 2,668,515 MICROMETER DIAL MECHANISM Thomas H. Evans, Fond du Lac Wis., assignor 'to Giddings & Lewis Machine Tool Company,

Fond du Lac, Wis., a corporation of Wisconsin Application August 23, 1951, Serial No. 243,275

4 Claims. (01. 116-424) This invention relates to adjustable micrometer dial indicating devices for machine tools.

An object of the invention is to provide an adjustable dial indicating device having a novel and improved type of clamping arrangement for disengageably securing a micrometer dial to a feed shaft or the like. By means of this invention, the dial may be clamped and unclamped with unusual facility and speed. Nevertheless, in accordance with a further object, the clamping arrangement of this invention provides an unusually reliable driving connection between the shaft and the dial, so that the dial, when clamped in selected position of adjustment, will be securely constrained against slipping on the shaft, even during abrupt starting and stopping of the shaft, which are common in modern machine tool practice.

A further object is to provide anadjustable dial mechanism which is safe and convenient, as

well as inexpensive to manufacture, and which includes a minimum number of parts.

Further objects, advantages, and features of the invention will appear from the following description of an illustrative embodiment constructed in accordance with the invention, the description being taken with the accompanying drawing, in which:

Figure 1 is a front face view of a dial panel having a pair of dial indicating devices embodying the features of the present invention; and

Fig. 2 is a plan view of the dial mechanism, partially in horizontal axial section along the line 2-2 of Fig. 1.

While the invention is susceptible of various modifications and alternative constructions, there such as ball bearings 14 and It, in a housing [2 which may constitute part of a feed drive unit (not shown) of a machine tool. The shaft may be suitably connected for synchronous drive to the feed drive unit by means of a gear I8 having an axial sleeve portion l9 splined onto the inner end of the shaft and supported by the bearing I4. As is conventional, the shaft I is provided in its outer end portion with an axial socket. adapted to receive a hand tool or an extension shaft.

The shaft l 0, as shown, is of stepped construction, comprising an inner end section Illa of small diameter to which the gear [8 is splined, an intermediate section l0b of larger diameter supported in the bearing [6, and an outer or forward end section I00 of still larger diameter projecting outwardly from the housing I2.

In the arrangement of Fig. 1, two dial indicating devices are shown as disposed in contiguous parallel relation. These devices are provided for connection to different drive units, but otherwise are alike in construction, so that a description of one will suii'ice for both. Each comprises an annular graduated dial 22 mounted on the outer end section lilc of the associated shaft ID in contiguous relation to a flat plate 13 secured to the front of the housing I2, and in effect constituting the base of the dial panel.

Provision is made for disengageably clamping the dial 22 to the shaft II] in any selected position of rotary adjustment relative to the shaft III. This end is achieved in the present instance by means comprising a peripheral flange 48 on the extreme outer end of the projecting shaft section 100, the inner side of the flange constituting an inwardly-facing annular abutment surface or shoulder 46. In opposed relation thereto is a flat annular ring 50 secured in position against an annular shoulder 60 defined at the juncture of the shaft sections lb and H10, and projecting radially outwardly beyond the diameter of the section I00 to present an annular abutment surface or shoulder 41.

A wedge clamping sleeve 24 is slidably disposed on the outer section l0c of the shaft I0 between the opposed abutment surfaces 46 and 56, and is constrained against rotation relative to the shaft by means of a key and slot connection 28, 30 between the shaft and the sleeve. Thus, the sleeve 24 is longitudinally adjustable on the shaft [0. End clearance for such adjustment is provided between the sleeve and abutment surfaces 46 and 56, as indicated.

The clamping sleeve 24 has an intermediate cylindrical portion 34 with which the dial 22 is always in interfitting engagement for relative sliding and rotary guiding support, an externally threaded outer end portion 42, and an inner end portion having an external conical or wedging surface 32 tapering toward the intermediate pilot surface 34. The dial 22 has a complementary internal conical wedging surface 36 for tight frictional engagement with the surface 32 of the sleeve 24, and an internal cylindrical surface 38 4 in guiding contact with the sleeve section 34.

In order to force the conical wedging surfaces 32 and 36 into gripping engagement, a ring nut 40 is suitably threaded onto the outer end portion 42 f the sleeve 24. The nut 40 may be screwed up by means of a knurled portion 44, so as to draw the sleeve 24 into the ring dial. In this way the external tapered surface 32 on the sleeve and the internal tapered surface 36 on the dial are clamped into frictional driving engagement. The tapered wedging surfaces and the screw threads provide a substantial mechanical advantage so that the dial can be clamped very securely to the sleeve.

The nut 40 and the dial 22 are rotatably confined end-to-end between the abutment surfaces 46 and 56 formed, respectively, by the retaining flange 48 on the outer end of the shaft l0 and the retaining ring 50 on the intermediate section Iflb of the shaft. Unscrewing movement of the nut 40 serves to push the sleeve 24 inwardly toward the ring 50, thereby disengaging the tapered surface 32 and 36. The shoulders 46 and 56 take up the thrust reactions on the nut and the dial. The dial 22 has a hub 52 having an inner end face 41 which is adapted to engage the ring 50. The sleeve 24 has an inner end face 54 which is spaced from the ring 50 a sufficient distance to provide the required clearance for endwise movement of the sleeve into and out of clamping engagement with the dial.

The retaining ring 50 is held in place against the shoulder 60 by means of a race ring 62 which forms a part of the ball bearing l6. An annular spacer 64 is positioned between the bearing race ring 62 and one end of a second race ring 58 forming a part of the ball bearing 14. The gear 18 is clamped against the other end of the race ring 66 by means of a nut 68 threaded on the inner end of the shaft I0.

Graduations are provided on the outer periphery of the dial 22 to indicate the extent of feeding movement represented by calibrated rotation of the shaft H), the movement being indicated in some convenient units such as thousandths of an inch. These graduations are disposed to move in relation to a stationary reference mark 12 on the panel plate 13. The dial has a knurled portion 14 to facilitate manual adjustment on the shaft l0.

Although the operation of the dial. indicating device will be apparent from the preceding description, a brief summary may be helpful. The dial 22 may be rigidly clamped to the shaft 10 in any selected position of rotary adjustment, for rotation with the shaft in synchronism with the feed drive unit of the machine tool. The graduations ill on the dial are suitably calibrated to indicate the extent of movement of the feed unit during the machine operation. Such clamping of the dial is effected by turning the nut 40 in a direction to draw the annular conical wedge portion 32 of the sleeve 24 outwardly into tight frictional driving engagement with the complementary tapered wedging surface 36 crime dial 22. Since the sleeve 24 moves axially, the clamping operation may be carried out without affecting the angular adjustment of the dial. a

To reset or otherwise adjust the dial 22, the nut 40 may be turned in the reverse direction to force the sleeve 24 inwardly, thereby disengaging the dial for free rotary adjustment on the pilot guide portion 38. Thus, for any position of translation of the machine feed unit, the dial 22 may be set to zero or any other desired initial reading in relation to the reference point 12. The wedge clamping surfaces 32 and 36 do not impose any limitation upon the adjustability of 4 the dial. In other words, infinitely fine adjustment is possible. After the adjustment has been completed, the nut 40 may again be turned in such a direction as to clamp the dial 22 in the newly selected position of adjustment.

It will be appreciated that the adjustment can be easily and quickly efiected, and that the clamping device is not only simple and inexpensive in construction, but also is most effective to prevent slipping of the dial relative to the shaft. The dial indicating device is unusually safe since it has no projections or spokes which might catch a finger or clothing.

1 claim as my invention:

1. In a feeding mechanism for a machine tool, a drive shaft including a cylindrical portion, an enlarged portion forming an outwardly extending flange at one end of the cylindrical portion, a reduced portion forming an inwardly extending shoulder at the opposite end of the cylindrical portion, a sleeve slidably carried on the cylindrical portion, interengaging parts on the sleeve and the shaft providing for relative longitudinal sliding movement thereof while preventing rela tive rotation thereof, external threads on the sleeve adjacent the flange, an external tapered portion on the sleeve at its end remote from the flange and tapering toward the threads, a ring dial carried on the sleeve between the threads and the external tapered portion and having an internally tapered surface positioned for clamp= ing engagement with the externally tapered portion of the sleeve, a nut carried on the threads for moving the sleeve into and out of clamping engagement with the dial, and a ring-shaped spacer carried on the reduced portion of the shaft against the inwardly extending shoulder to form an outwardly extending shoulder for confining the dial and the nut on the shaft against substantial end play.

2. In a feeding mechanism for a machine tool, a drive shaft, a sleeve slidably carried on the shaft, interengaging parts on the sleeve and the shaft providing for relative longitudinal sliding movement thereof while preventing relative riotation thereof, external threads on the sleeveat one end thereof, an externally tapered wedging portion on the sleeve at the opposite end tapering toward the threads, a dial slidably oarried on the sleeve between the threads and the externally tapered portion, said dial having an internally tapered wedging surface positioned for clamping engagement with the externally tapered portion of the sleeve, a nut carried on 3. A dial clamping mechanism for a machine tool, comprising a shaft, a sleeve on the shaft carried for positive rotation with the shaft and sliding movement along the shaft, 2', ring dial carried, on the sleeve for rotation relative thereto, means for preventing any substantial endwise movement of thedial relative to the shaft, the dial and. the sleeve having complementary clamping surfaces, and a threaded member acting between the dial'and the sleeve to move the dial into and out of clamping engagement with the sleeve.

4. In a feeding mechanism for a, machine tool, the combination comprising a shaft, a sleeve slidable along the shaft, means for preventing'rela 5 tive rotation of the sleeve and the shaft, a ring dial carried on the sleeve for rotation relative thereto, interengageable complementary tapered clamping surfaces on the dial and the sleeve, an externally threaded portion on the sleeve, an internally threaded ring nut carried on the threaded portion of the sleeve for moving the sleeve endwise into and out of clamping engagement with the dial, and means on the shaft providing a, pair of opposite shoulders for preventing any substantial endwise movement of the dial and the nut, said dial and nut being disposed between the shoulders in end to end abutting relation.

THOMAS H. EVANS.

References Cited in the file of this patent UNITED STATES PATENTS 

